It is well known that distributed denial of service attacks are a major threat to the Internet today. Surveys of network operators repeatedly show that the Internet's stakeholders are concerned, and the reasons for this are clear: the frequency, magnitude, and complexity of attacks are growing, and show no signs of slowing down. With the emergence of the Internet of Things, fifth-generation mobile networks, and IPv6, the Internet may soon be exposed to a new generation of sophisticated and powerful DDoS attacks. But how did we get here? In one view, the potency of DDoS attacks is owed to a set of underlying architectural issues at the heart of the Internet. Guiding principles such as simplicity, openness, and autonomy have driven the Internet to be tremendously successful, but have the side effects of making it difficult to verify source addresses, classify unwanted packets, and forge cooperation between networks to stop traffic. These architectural issues make mitigating DDoS attacks a costly, uphill battle for victims, who have been left without an adequate defense. Such a circumstance requires a solution that is aware of, and addresses, the architectural issues at play. Fueled by over 20 years worth of lessons learned from the industry and academic literature, Gatekeeper is a mitigation system that neutralizes the issues that make DDoS attacks so powerful. It does so by enforcing a connection-oriented network layer and by leveraging a global distribution of upstream vantage points. Gatekeeper further distinguishes itself from previous solutions because it circumvents the necessity of mutual deployment between networks, allowing deployers to reap the full benefits alone and on day one. Gatekeeper is an open-source, production-quality DDoS mitigation system. It is modular, scalable, and built using the latest advances in packet processing techniques. It implements the operational features required by today's network administrators, including support for bonded network devices, VLAN tagging, and control plane tools, and has been chosen for deployment by multiple networks. However, an effective Gatekeeper deployment can only be achieved by writing and enforcing fine-grained and accurate network policies. While the basic function of such policies is to simply govern the sending ability of clients, Gatekeeper is capable of much more: multiple bandwidth limits, punishing flows for misbehavior, attack detection via machine learning, and the flexibility to support new protocols. Therefore, we provide a view into the richness and power of Gatekeeper policies in the form of a policy toolkit for network operators. Finally, we must look to the future, and prepare for a potential next generation of powerful and costly DDoS attacks to grace our infrastructure. In particular, link flooding attacks such as Crossfire use massive, distributed sets of bots with low-rate, legitimate-looking traffic to attack upstream links outside of the victim's control. A new generation of these attacks could soon be realized as IoT devices, 5G networks, and IPv6 simultaneously enter the network landscape. Gatekeeper is able to hinder the architectural advantages that fuel link flooding attacks, bounding their effectiveness.

Despite its potential to enhance the mental health of college student populations, the efficacy of gatekeeper programs in connecting suicidal students with professional help is unclear. Potential negative side effects of peer helping programs, such as gatekeeper training, are rarely examined and there is not a sufficient body of evidence documenting the efficacy or safety of peer helping programs, despite their widespread use. The challenge of implementing a safe and effective peer based gatekeeper campus suicide prevention effort lies in balancing the benefits of connecting suicidal students to professional help more often and sooner, with the potential adverse mental health impacts of participation on gatekeepers. This study examines how a gatekeeper training program might increase suicidal student help seeking and measures the mental health impact of participation on Resident Assistants (RAs) trained in suicide prevention. This study will explore whether a more intensive helping role by the RA amplifies the effect of referring and securing professional help for suicidal students. This study also measures how differing the intensity of help provided by RAs impacts the gatekeepers’ own stress and suicidality levels. RAs will be trained under high versus low intensity helping conditions. RAs in the low intensity helping condition will be trained to identify potentially suicidal students and refer them for professional help. RAs in the high intensity helping condition will be trained to identify potentially suicidal students, engage them in a quasi-professional helping role, and refer them to professional help. This study will also explore whether promotion of telephone counseling as a helping resource will impact referrals to and utilization of professional help, either in-person or through telephone counseling. / text

The purpose of the study was to identify the effectiveness of an online suicide prevention gatekeeper training at the University of Iowa compared to previous research, other gatekeeper trainings, and to assess differences between faculty and staff trainees. Participants were faculty, staff, and students at the University of Iowa that completed the Kognito College Students or the Kognito Faculty and Staff module. To determine the effectiveness, participants completed program evaluation surveys at pre-training, immediate post-training, and six-months after completion of the training. The surveys assessed four gatekeeper appraisal scales: Gatekeeper Knowledge and Beliefs, Gatekeeper Reluctance, Gatekeeper Self-Efficacy, and Gatekeeper Experiences. The first three scales assessed the participant’s perception of their current gatekeeper skills and the last scale assessed gatekeeper behaviors in which the gatekeeper engaged. Results of the study indicate that the training was comparably effective to previous research on Kognito and other in-person gatekeeper trainings in increasing gatekeeper skills. Furthermore, there were no significant differences in performance between faculty/staff and student participants. There is currently insufficient evidence to suggest that a specific gatekeeper training is significantly more effective than any other training. Future research, should continue to investigate the effectiveness of suicide prevention approaches and evaluate the specific factors which make gatekeeper trainings effective.

(english) The thesis deals with the environmental journalist, I use gatekeeper concept. The aim is to identify working routines and relationship with environmental and nature. In the first part, I complicate the theoretical basis. I first concerned with social constructionism of issue, media communication and key terms in media and environment. In empirical part is used the qualitative research strategy - an analysis of interviews with environmental journalists from news journals, weekly magazines and websites and analysis of information sources. I described relationship, opinions and values of environmental journalists to environment and nature. I identified the working routines and I completed it by the analysis of information sources. Important information sources are expert, non governance organization, states institutions in the environmental area. Experts and states institutions are primary defining. This research confirmed authority orientation of news. Journalists feel the autonomy in selection of topic, but I recorded pressures and controls from the media organizations. Journalists have a close relationship to nature and the environment, its protection is seen as important. Conservation lies in the modesty and sustainability.

Rapid and well-orchestrated action potential propagation through the myocardium is essential to each heartbeat. Gap junctions comprising primarily Cx43 reside within the intercalated discs connecting cardiomyocytes, effecting not only direct intercellular electrical coupling, but the localization of other junctional structures and ion channels. Alterations in Cx43 expression occur in essentially all forms of heart disease and is therefore a topic of intense study. Posttranslational modification of Cx43 is understood to impact trafficking, conduction, and stability. Altered Cx43 phosphorylation is well described during pathological remodeling of gap junctions in response to cellular stress. Research has revealed how phosphorylation of specific residues elicit specific effects on Cx43, but the complexity of this process has left much unknown. In particular, the role phosphorylation of a triplet of double serine residues, Ser365, Ser368, and Ser373, plays in GJ function and Cx43/14-3-3 interaction has been called into question. Using an ex vivo whole heart ischemia model we find a decrease in pS368 in mice lacking the ability to phosphorylate S365 and S373 while under stress. In vitro transfection of human induced pluripotent stem cell-derived cardiomyocytes when stressed with PMA were also carried out. These data allow us to piece together the exquisite interplay of gatekeeper phosphorylation events upstream of channel closure, altered protein-protein interactions, and gap junction internalization and degradation. It is hoped that our increasing understanding of this important area of gap junction biology will facilitate better understanding of arrhythmogenesis, and potential therapeutic strategies to restore or preserve normal electrical coupling in diseased hearts. / Master of Science / The heart, an electrically active organ, relies on the propagation of an electrical signal throughout its entirety in order to produce a healthy heartbeat. In order to do so, the heart uses specialized muscle cells known as cardiomyocytes which can not only contract but pass along chemical signals to the cardiomyocyte next in line to signal it to contract as well. The passage of signals occurs through protein units called gap junctions and are made predominantly of Cx43 proteins in the heart. Gap junctions look and function like tubes that travel from the inside space of one cell to the other and allow a flow of small molecules to occur; these small molecules, namely ions, are part of the signal needed to initiate contraction in the adjacent cell. Cx43, like many proteins in our bodies, is slightly altered after it is produced through a process known as posttranslational modification. This allows the cell to alter the localization and function of the protein and tailor it for the needs of the cell. Rather than changing the backbone composition of the protein, small chemical groups are attached, and this imparts a change to how the protein interacts with other proteins or its environment. In particular, one form of modification is known as phosphorylation where a phosphate group is attached to the protein at specific locations along its chain. Cx43 too can be phosphorylated, and while under pathological stress, such as a lack of oxygen or infection, cardiomyocytes increase the amount of phosphorylated Cx43 at a site known to cause pathological changes to the function of Cx43. These changes include how well the gap junctions can transmit signals or associate with other proteins and, in the heart, can predispose the development of arrhythmias or unhealthy heartbeats. However, not all phosphorylation is bad and phosphorylation at other locations also occurs during normal healthy functions of the cardiomyocyte can affect how other sites along Cx43 are phosphorylated. The process of one phosphorylated site affecting another is known as the gatekeeper effect and add a new layer to our understanding of how cells use phosphorylated Cx43 to fine tune its effects. Using cells that do not produce their own Cx43 and subsequently giving them the instructions to produce specific forms of mutant Cx43 that can and cannot be phosphorylated at specific sites, we can understand with greater detail of how cardiomyocytes respond to stress and how some of those responses can be pathological. This will allow future research into the creation of therapies that prevent negative Cx43 phosphorylation after illness, potentially avoiding the development of dangerous arrhythmias.

[pt] O estudo analisa processos de categorização da profissão de secretária na entrevista de pesquisa entre a pesquisadora e a gatekeeper (Roberts, 2000) responsável pela seleção, que acessa informações sobre empregador e empregado, compondo o perfil do candidato. O objetivo da pesquisa é identificar as categorias presentes nos dados, sua função, e as formas como as participantes as trouxeram interacionalmente, visto que estas formas compõem os significados discursivos das categorias. A análise, qualitativa interpretativa, adota uma perspectiva micro sócio-interacional. A pesquisadora participa da entrevista, procurando obter uma visão intradiscursiva dos dados. Sobre teoria e análise, estudos de processos de categorização de membros e conhecimento senso-comum (Sacks, 1992; Garfinkel, 1967; Polanyi, 1969) são essenciais para entender as atividades de significação das participantes. Estudos sobre entrevistas de emprego (Silveira, 1998)demonstram a influência interacional do contexto institucional. Igualmente relevantes são pesquisas sobre vozes discursivas (Günthner, 1997) e mapeamento interacional (Sarangi, 2007). Assim, esta pesquisa observa a categorização em seus contextos, formas e vozes. Os resultados da análise revelam que o processo de seleção é influenciado pela categorização. Uma teia de relações entre categorias de membros, atividades, aparência, entre outras, ocorre nos dados. Esta pesquisa pretende contribuir para as teorias da categorização, e para os estudos discursivos sobre as entrevistas e seleções de emprego. / [en] This study analyses categorization processes about the secretary in a research interview between the researcher and the gatekeeper (Roberts, 2000) responsible for selection, who accesses information about employer and employee, building the candidate`s profile. The aim of the research is to identify the categories, as well as their function in the data, and the forms by which the participants interactionally brought them to speech, since they compose categories` discursive meanings. On the analysis, qualitative interpretative, a micro socio-interactional perspective is adopted. The researcher participates on the interview, obtaining an intra-discursive view of data. On theory and analysis, studies about membership categorization processes and about common-sense knowledge (Sacks, 1992; Garfinkel, 1967; Polanyi, 1969) are essential to understand the participants` meaning activities. Studies about job interviews (Silveira, 1998) display the interactional influence of the institutional context. Also relevant are studies about discursive voices (Günthner, 1997) and interactional mapping (Sarangi, 2007). Therefore, this research, observes categorization in its contexts, forms and voices. The analytical results reveal the influence of categorization on the selection process. A web of relationships, between categories of members, activities, appearance and others, takes place during the discourse in the data. This research aims to contribute to the theories of categorization and also to discourse studies about job interviews and selections.

No description available.

[pt] A internet permite reunir – simultaneamente e no mesmo ciberespaço informativo – os jornalistas, os leitores, as fontes de informação e as instâncias organizadas da sociedade. Neste ambiente, em que todos têm voz, o papel do jornalista é posto em xeque. Frente a uma crise de identidade jamais enfrentada, o jornalista on-line vem reconfigurando suas funções. Esta pesquisa analisou as rotinas produtivas nos sites de O Globo e do Extra para verificar como a web adicionou papéis a estes profissionais. O ponto de partida foi o estudo pioneiro sobre a função do jornalista na seleção das notícias realizado por David White, em 1950, para verificar a pertinência do papel de gatekeeper no jornalismo on-line. O conceito gatewatcher, que define o jornalista on-line como um observador à procura de conteúdos do interesse de seu público, também foi aplicado. Na sequência, a antiga teoria que relaciona o jornalista a um mediador foi revista, à luz da internet. Observamos que, assim como o modelo de comunicação horizontal da internet traz uma nova camada de informações ao jornalismo on-line, ele também superpõe camadas funcionais aos jornalistas. A produção noticiosa proveniente de canais interativos, como blogs e enquetes, é adicionada aos processos tradicionais de apuração, edição e distribuição da notícia que sempre caracterizaram o jornalismo off-line. Entretanto, a crescente participação do público impõem novas funções aos profissionais na redação. Sustentamos que o jornalista on-line está firmando sua identidade em um novo alicerce: o de mobilizador da audiência, atuando para engajar seu público em torno de diversas causas. / [en] The internet enables the assembling of – concurrently and in the same informative cyberspace – journalists, readers, information sources and society organized agencies. In this scenario, in which everybody has a say, the journalist role is called into question. In view of an identity crisis never seen before, the on-line journalist has been resetting his/her roles. The present research has analysed the productive routines in O Globo and Extra web sites to see how the internet added roles to these professionals. The starting point was David White s pioneering study about the journalist role in selecting news, in 1950, in which he ascertains the relevance of the gatekeeper s role in the on-line journalism. The gatewatcher concept, which defines the journalist on-line as an observer searching for content that may be of his audience interest, has also been applied. Following, the old theory which relates the journalist to a mediator has been reviewed, vis-à-vis the internet. We observe that, as the horizontal communication model of the internet brings a new layer of information to the on-line journalism, it also superimposes functional layers to the journalists. The news production from interactive channels, like blogs and polls, is added to the traditional processes of verification, editing and distribution of news that always characterized off-line journalism. However, increasing public participation imposes new roles for professionals in the newsrooms. It was possible to see how the on-line journalist is establishing his identity based on a new pillar: as an audience mobilizer, seeking the public engagement to support certain causes.

The need for regulation of the credit rating agencies (CRAs) arose due to their role in the subprime mortgage crisis. The CRAs awarded risky securities '3-A' investment grade status and then failed to downgrade them quickly enough when circumstances changed which led to investors suffering substantial losses. The causes identified by the regulators for the gatekeeper failure were conflicts of interest (as the issuers of these securities pay for the ratings); lack of competition (as the Big Three CRAs have dominated the market share); and lack of CRA regulation. The regulators, both in the US and EU, have tried to address these problems by introducing soft law self-regulation in accordance with the International Organisation of Securities Commissions Code and hard law statutory regulation such as that found in the "Reform Act" and "Dodd-Frank Act" in the US and similar provisions in the EU. This thesis examines these provisions in detail by using a doctrinal black-letter law method to assess the success of the regulators in redressing the problems identified. It also examines the US case law regulation relating to the legal liability of CRAs. The findings are that the US First Amendment protection, exclusion clauses and case law, all lack a deterrent effect on the actions of CRAs. As CRAs have escaped substantial damages, investors are left uncompensated for their losses. The thesis concludes that the issues of conflicts of interest and an anti-competitive environment persist. This thesis recommends the introduction of liability for the CRAs based on the Australian Bathurst case and which should be put in a statutory footing, including the requirements that are needed for making exclusion clauses effective. Rotation of CRAs for every three years would minimise the conflicts of interest. Regulators should require CRAs to purchase professional indemnity insurance, if available, to compensate investors.

My research examines the importance of a particular form of cross-group brokerage in social networks wherein a person represents a bridge between his or her group and people belonging to a different group. Prior research on network brokerage and leadership emergence has failed to distinguish between brokerage in general and the kind of boundary-spanning between groups that is the focus of my research. Moreover, what we currently know about social network brokerage and leadership emergence comes either from highly abstracted laboratory-based work, or it comes research in relatively traditional work organizations with clear formal structures. It is unclear whether prior research from traditional organizational settings can be applied to nontraditional organizations in the so-called “creative industries,” which are the focus of my research. The core hypotheses my research examines are: (1) Do individuals whose friendship networks help them bridge between groups emerge as leaders in the eyes of others? And (2) Are people who are socially perceptive and socially skilled better at leveraging such boundary-spanning positions to win nominations of leadership from others? Data from the study come from interview and survey data from four different musical orchestras based in Korea.